Hear me out.
Originally, Valravens could replace towers. We figured this out because Valravens could replace Zuul’goth, and that made us sad. So before we actually got in the situation with towers, the devs made a compromise: if a Valraven would appear during a 4x tower match, it doesn’t appear but you get the sigils anyway if you win. That’s pretty fair on our end. So the only way to lose bonus sigils is to lose a match. That’s pretty fair.
If raven towers replace this mechanic entirely, it seems reasonable to believe this means on average you will lose sigils. Sometimes you’re going to get unlucky and that tower’s going to fill up. Used to that just meant you took a beating. Now it means a % chance you don’t get sigils and lose a tower point.
Is this the case? Or are there still invisible Valravens?